In the related art, a system is known, which includes a server device and a plurality of information terminals that can communicate with each other via a wireless communication network system, and in which the server device detects a presence or absence of a traffic congestion based on position information of an information terminal carried by an occupant of a vehicle, the detection result is associated with map information and transmitted to the information terminal, and then, the information terminal displays the presence or absence of the traffic congestion on the map (for example, refer to Patent Document 1).